Scratchbuild of my own design

Hello friends, I am just starting to build a scratch built submarine by my own design and own drawings .
I am going to post a buildlog here to get some feedback and advice.
Briefly about me :
My name is Mats Wergeland , aged 45 and live outside Stockholm in Sweden .
I have built models all my life. Mostly RC aeroplanes but now it's time for a submarine .
The idea of the project is to keep it fairly simple to get forward pretty fast. Then i can always modify and add features later.
The starting material is a PVC pipe measuring 160 mm in outside diameter. This is the WTC.
Nose cone , aft cone and topdeck will be cast in fiberglass. These parts are waterfilled when diving .
Overall length is approximately 1360 mm/ 53”, height 340 mm/ 13” + mast etc.
Estimated weight becomes 9.3 kg/ 20,5 P dry weight.
Functions will be: Diving with the help of bladder , diverudders , steering, trottel and lights.
Power source is a lead acid battery 12V/14Ah . Preliminäry motor is an 12V car fan-engine.
This build wil take some time so be patient.

Some trigonometry to determine the required volume for moving from top float to just below surface. Turns out to be 1,2 l./0,32G.

WTC with some various components at the construction table.
Shaft, propeller etc. were purchased from www.cornwallmodelboats.co.uk .
Waterpump is an refulingpump for aeroplanes. It has yet to be evaluated in terms of flow and preasurehight. My aim is to dive to an max depth of 2 m/ 6,6 F.